Shingle with Reinforcement Layer

ABSTRACT

A shingle, a method of making it, and a roof embodying the shingle is provided, in which an exterior surface of the shingle is provided with an attached reinforcement layer through which fasteners may be applied when the shingle is applied to a roof.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 14/307,677, filedJun. 18, 2014, which, in turn is a continuation of U.S. application Ser.No. 14/284,492 filed May 22, 2014, which, in turn is a continuation ofU.S. application Ser. No. 14/068,306 filed Oct. 31, 2013, which, in turnis a continuation of U.S. application Ser. No. 13/855,820 filed Apr. 3,2013, now U.S. Pat. No. 8,615,968 which, in turn is a continuation ofU.S. application Ser. No. 13/788,029 filed Mar. 7, 2013, now U.S. Pat.No. 8,592,025 which, in turn is a continuation of U.S. application Ser.No. 13/462,159 filed May 2, 2012, now U.S. Pat. No. 8,409,689 which, inturn, is a continuation of U.S. application Ser. No. 12/857,868 filedAug. 17, 2010, now U.S. Pat. No. 8,173,243 which in turn is acontinuation of U.S. application Ser. No. 12/422,506 filed Apr. 13,2009, now U.S. Pat. No. 7,781,046 which in turn is a continuation ofU.S. application Ser. No. 11/421,893, filed Jun. 2, 2006, now U.S. Pat.No. 7,537,820 which, in turn, is a continuation-in-part of U.S.application Ser. No. 10/871,911, filed Jun. 18, 2004, now U.S. Pat. No.7,118,794, which, in turn is a continuation of application Ser. No.10/288,747, filed Nov. 6, 2002, now U.S. Pat. No. 6,758,019.

BACKGROUND OF THE INVENTION

In the manufacture of shingles, it has been known that when shingles aresubjected to strong winds, the winds can engage the lower edges or tabportions of the shingles, and bend them upwardly.

On occasion, under strong winds, the tabs can bend upwardly in amountssufficient that the inherent, internal resistance to substantial bendingand perhaps cracking, can be overcome, in that the mat that is formedinternally of the shingle, and the asphaltic material on the surfaces ofthe shingle, may not be sufficient to withstand certain wind conditions.

Various approaches have been made to resist shingle failure via crackingand the like, not all with substantial success.

For example, strips of adhesive material along lower ends of tabs ofshingle have been applied, which, when subjected to hot weatherconditions, soften an amount sufficient that such adhesive will adhereto the next-subjacent shingle on a roof, eventually harden andthereafter resist upward deflection of shingle tabs under severe windconditions. However, such adhesive sometimes dries out, or becomesbrittle over time, offering reduced adhesion. In other cases, strongwind conditions can exist during high temperature situations when suchadhesive located under tabs remains soft, and thus the adhesive does notfunction in its intended manner.

Other approaches have resorted to thickening the mat and/or asphalticmaterial, to offer internal resistance to bending, but nonetheless,failures due to wind-related bending of tabs of shingle continue toexist.

SUMMARY OF THE INVENTION

The present invention is directed toward providing a shingle, wherein aseparate, exterior reinforcement layer is provided outside the rearsurface of the shingle, with such layer comprising a material that isnot coated or covered by any thick layer of asphalt or the like.

Accordingly, it is an object of this invention to provide a novelshingle having a layer on the lower surface of the shingle, thatcomprises a reinforcing material.

It is a further object of the invention to accomplish the above objects,wherein the reinforcement layer comprises a scrim material.

It is another object of this invention to accomplish the above objects,wherein the reinforcing material extends into either or both of the tabportion of the shingle and the headlap portion of the shingle.

It is a further object of this invention to accomplish the object above,wherein the reinforcing material extends into a nailing zone or otherfastening zone of the shingle through which nails or other fastenerspass upon securing the shingle to a roof.

It is a further object of this invention to provide a method of makingshingles in accordance with the objects set forth above.

Other objects and advantages of the present invention will be readilyunderstood upon a reading of the following brief descriptions of thedrawing figures, detailed descriptions of the preferred embodiments andthe appended claims.

BRIEF DESCRIPTIONS OF THE DRAWING FIGURES

FIG. 1 is a rear elevational view of a shingle made in accordance withthe prior art.

FIG. 2 is an illustration like that of FIG. 1, but wherein the shingleis shown to have a reinforcement layer applied to the rear surfacethereof, in accordance with the present invention.

FIG. 2A is a right side view of the shingle of FIG. 2.

FIG. 3 is an illustration like that of FIG. 2, but wherein thereinforcement layer extends farther into the tab portion of the shinglethan in the embodiment of FIG. 2.

FIG. 4 is a side view of the shingle of this invention shown resistingtorque applied to the tab portion of the shingle under a wind-liftingforce that bends the shingle upwardly at approximately 45°.

FIG. 4A is a vertical sectional view of the shingle of FIG. 4, asapplied to a roof of steep slope.

FIG. 4B is a top view of an exemplary laminated roofing shingle.

FIG. 4C is a side edge elevation view of two prior art laminatedshingles as they are applied to a roof deck, showing one correctlyapplied fastener and one incorrectly applied fastener.

FIG. 4D is a top plan view of a laminated shingle according to thepresent invention.

FIG. 5 is a graph showing an example of the absorption of wind-liftingtorque upon bending a particular weight of shingle through variousangular degrees and the improvement of providing a reinforcementmaterial in accordance with this invention under the same liftingconditions.

FIG. 6 is a view similar to that of FIG. 5, for a somewhat differentweight of shingle, and a different weight of mat for the shingle.

FIG. 7 is an illustration similar to that of FIGS. 5 and 6 for adifferently constructed shingle.

FIG. 8 is a graph similar to that of FIG. 7, for a shingle have a widerreinforcement layer.

DETAILED DESCRIPTIONS OF THE PREFERRED EMBODIMENTS

Referring now to the drawings in detail, reference is first made to FIG.1, wherein a prior art shingle is illustrated as comprising a shinglegenerally designated by the numeral 10, constructed as a mat ofpreferably fiberglass mesh, having asphalt, or some other form ofbitumen material impregnated therein, and forming layers on each surfacethereof, with a granular material on each exposed surface. On the upperexposed surface, will be granules of a size desired to resist sun andother weather conditions, and on the opposite, or undersurface 11, therewill be preferably smaller granules of a mica, sand or like material,for example. The shingle 10 has a headlap portion 12 and a tab portion13, having slotted openings 14 dividing the tab portion 13 into a numberof discrete tabs 15. On the undersurface 11 there is provided preferablybut optionally a sheet of release paper or tape 16, which is removedwhen the shingle is installed on a roof, but which, for stackingshingles for shipment prevents the shingle from sticking to a subjacentshingle in the stack, which subjacent shingle has a similarly locatedstrip of adhesive material, such as more bitumen, extendinglongitudinally from edge 17 to edge 18, on the front surface of thesubjacent shingle.

The basic shingle of FIG. 1 may be made in accordance with the teachingof U.S. Pat. No. 6,092,345, U.S. Pat. No. 6,145,265, or U.S. Pat. No.5,822,943, the complete disclosures of all of which are hereinincorporated by reference.

With specific reference to FIGS. 2 and 2A, it will be seen that ashingle 20 is presented, having a rear surface 21, with a release strip26 running from left to right across the lower end of a headlap portion22, between edges 27 and 28, and with the tab portion 23 of the shingle20 comprising a plurality of tabs 25 separated by vertical, spaced apartslots 24.

A nailing zone “N” exists on the front surface of the shingle 20,generally located above the release tape or strip 26, running betweenedges 27, 28 above the slots 24. Essentially, the shingle 20 is similarto that of the shingle 10 of FIG. 1, but with a reinforcement layer,preferably of fiberglass, of a width between approximately 3 and 8 cm,and preferably about 2½ inches, that may comprise a scrim layer 29 isadded on the rear 21 of the shingle 20, across the upper end of the tabportion 23, and across the lower end of the headlap portion 22, as shownin FIG. 2, covering the area shown in FIG. 2, as well as the areadisposed beneath the release strip 26, along the lower end of theheadlap portion 22 between edges 27 and 28, as shown in FIG. 2. Duringthe construction of the shingle of FIG. 2, the reinforcement layer 29 isthus applied before the release tape 26 is applied.

Thus, the reinforcement layer 29 may be a fiberglass scrim and willpreferably be a woven construction, involving woven strands disposed atright angles to each other, with a preferred density of, for examplenine strands in the vertical direction and nine strands in thehorizontal direction per square inch of scrim (9×9 per in²).

With reference to FIG. 3, it will be seen that a shingle 30, much likethe shingle 20, is provided, having a rear surface 31, having a headlapportion 32 and tab portion 33, with the tab portion comprising aplurality of tabs 35 separated by slotted openings 34, with a releasestrip 36 extending between left and right edges 37 and 38, and with ascrim 39 located beneath the release strip 36 as with respect to theembodiment of FIG. 2, but extending downwardly farther into the tabs 35,as shown, in that the scrim 39 is essentially about 6 inches wide,running from the upper edge of the release strip 36, into the tabs, asshown.

It will be apparent that other lengths of scrim 29, 39, will beappropriate depending upon the desired resistance to bending under windconditions, as will be addressed hereinafter.

The scrim layers 29, 39, will not be coated with a bitumen or otherasphaltic material, nor will they have granules applied thereto, suchthat the filaments of the scrim 29, 39, especially those extendingvertically as shown in FIGS. 2 and 3, can resist bending and resistfailure in the form of the likelihood of forming horizontal cracksacross the upper end of the tab portion of the shingle, when the shingleis bent upwardly within its elastic limit under forces applied by windsor other upward lifting forces.

The scrim may have a density other than the 9×9 per in². addressedabove, such as but not limited to 8×8 per in² or 7×7 per in², and may beof various compositions other than fiberglass, such as polyester,polypropylene and/or nylon. In lieu of a scrim, the reinforcement layers29, 39 may comprise woven or nonwoven thin fabric, plastic film, paper,parchment, foil or the like, either embedded in the asphaltic layer onthe rear of the shingle or adhered to the rear of the shingle by anadditional post-applied thin layer of asphaltic or non-asphalticadhesive. The reinforcement layer 29, 39, will be adhered to the rearsurface 21, 31 of the shingles of this invention, by means of anysuitable adhesive, such as a bitumen or the like, or any other adhesive.

With reference now to FIG. 4, it will be seen that a roof 40 isfragmentally illustrated, having a shingle 41 fastened thereto by meansof a nail, staple, 42 or the like, through the nailing or fastening zoneof the shingle as described above with reference to FIG. 2, andtherefore through the reinforcement layer 29. When wind forces occur inthe general direction indicated by the arrow 43 in FIG. 4, such thatthey tend to bend the tab portion 44 of the shingle upwardly to an angle“a”, as shown by the dotted arrow 45, the scrim 46 applied to theundersurface of the shingle 41 will tend to resist upward bending of theshingle tab portion 44, largely because of the resistance to suchbending that is provided by the reinforcement layer 29, 39 as shown inFIGS. 2 and 3 which will resist stretching and thereby inhibit bending.

It will be understood that up to some level of force applied by wind inthe direction 43, the shingle tab portion 44 will bend within itselastic limit in accordance with Hook's law. In this regard, any givenweight of shingle, under any particular conditions, will have its ownmodulus of elasticity, which is a measure of the stiffness or rigidityof the shingle, and within which the shingle will return to itsoriginal, flat condition when the force of wind is removed.

With reference to FIG. 4A, the vertical section of a shingle 41, asapplied to a roof 40 is illustrated, with the roof 40 being similar tothat set forth above and the attendant description thereof. It will beseen that the reinforcement material 46, underlying the shingle 41, isengaged by the nail or other fastener 42 that is applied through thenailing zone of the shingle 41, with the shank 49 of the fastener 42being in secure engagement within the roof 40, and passing through thereinforcement material 46. Thus, especially when the reinforcementmaterial 46 is a scrim, a fabric, or any other material that would tendto resist tearing, the fasteners 42 holding shingles on a roof 40, ofthe steepness shown, or even a steeper roof, would tend to resistmovement of the shingle 41 under conditions of intense heat, and perhapsbeing walked upon by a worker, from tending to become disengaged fromthe roof, because the fasteners catch in the reinforcement material 46,and resist shingle 41 movement, for example from sliding down along theroof in the direction of the arrow 48.

The preferred laminated roofing shingle 103 in accordance with thepresent invention is shown in FIG. 4B. The preferred laminated shingle103 broadly comprises upper and lower layers 105, 107, respectively,joined by sealant 109. When viewed from the top or front, the shinglecomprises a headlap area 110, a sealant line 115, a nail zone 120, andan exposed face area 125. The exposed face area 125 includes the portionof upper layer 105 including one or more cutouts which from a pluralityof tabs 135, and the exposed portions of lower layer 107 underlying saidportion of upper layer 105.

Although the shingle 103 depicted in the drawings is a two-ply laminatedshingle, other shingle configurations of varying shapes and sizes (e.g.,multi-ply shingles having two or more layers, three-tab or multiple tabshingles) are equally within the scope of the present invention.

This so-called nail zone in the prior art shingles is shown in FIG. 4C.A shingle 150 in the first course of shingles is nailed to the roof deck154 with a plurality of nails 156, only one of which is shown for thelowermost shingle 150. Nail 156 is shown correctly applied. The nextadjacent shingle 151 in the next course of shingles is placed overshingle 150 in the first course and is nailed in place in a like manner.However, as may be seen, and to illustrate the problems associated withimproperly applied fasteners, nail 155 is shown driven through only onelayer of shingle 151 and in a position such that the nail is driventhrough only one layer of the laminated sheets. Nail 155 is thus driventhrough the shingle outside of the nail zone. The improper nailing is adirect result of a relatively narrow nail zone. And the nail zone isnecessarily relatively narrow in view of the need to make the backingsheet no greater than ½ the width of the top sheet, which as mentionedis a design feature that facilitates stacking and bundling. However, thecloser the nails are placed to the lowermost edge of the nail zone, thegreater the possibility that water will leak through the nail hole, orthat there will be exposed nails on the roof. Furthermore, roofintegrity is comprised since the back sheet of shingle 151 may literallyslip out from its attachment to the top sheet when the roof becomes hotand the adhesive material sloughs.

Referring to FIG. 4D, shingle 250 may be seen as having a top sheet 254with alternating tabs 262 leaving visible cutout portions 252 showingbacking sheet 251, resulting in alternating tabs 262 and cutout portionsformed along the lower longitudinal edge 264 of the top sheet 254. Ascan clearly be seen in FIG. 4D, the cutout portions are of variouslongitudinal dimensions left-to-right between edges 263 of tabs, suchthat portions of backing sheet 251 are visible through the openings 252between tabs.

Reference will now be made to the graphs of FIGS. 5-8, forrepresentative benefits achieved by using a scrim applied to shingles inthe manner discussed above, for various weights of shingles havingdifference mats, and under the same temperature conditions, forcomparison purposes.

With reference to FIG. 5, it will be seen that a shingle version isidentified as version 3, with its control identified as version 3C, eachbeing a 250 lb. shingle, in weight per square (1 square equals enoughshingles to cover 100 ft² of roof) and with 2.5 lb. mat. (in weight per100 square feet of mat). In each case, the samples were tested at 30° F.The ordinate or vertical measure in the graph is the percent of theapplied force or load that is absorbed by the shingle at a given degreeof angular bend, as shown in degrees on the abscissa or horizontal lineof the chart, under a fixed torque applied to the shingle tab portion,of 6.0 inch-lbs. It will be seen that for the control shingle of FIG. 5,failure, or inelastic bending to the point that the shingle does notreturn to its original, flat condition when the force of wind isremoved, occurred at about 40° of angular bend, with failure beingdefined as a crack or permanent bend as distinguished from a bend withinthe elastic limit. However, for the shingle having a scrim of 2½ inchesin width, as shown in FIG. 2, it will be seen that in FIG. 5 thatshingle with the scrim remained within its elastic limit up to about 60°of angular bend, prior to failure. It will thus be seen that thespecimen graphed in FIG. 5 having a scrim applied thereto absorbed about75% of the torque load applied thereto, for a bend of the tab portion ofthe shingle of about 60°, before failure.

Referring now to FIG. 6, wherein a version 4 was matched against acontrol version 4C, for a 235 lb. weight of shingle having a 2.6 lb.mat, again at 30°, the control version absorbed about 60% of the torquethat was applied, up to about 40° of angular bend, whereas the specimengraphed in FIG. 6 having a 2½ inch wide scrim applied thereto absorbedabout 77% of the applied torque load, when subjected to a bend of 60°,before failure.

Referring now to FIG. 7, wherein yet another shingle 5 was testedagainst a control shingle 5C, with the shingle graphed in FIG. 7, likethat of FIG. 6, also being a 235 lb. weight per stack, but having a 2.5lb. mat, and likewise having a 2½ inch wide scrim, it will be seen that,whereas the control version absorbed only about 55% of the appliedtorque at about a 40° bend, the version with the scrim applied theretoabsorbed about 70% of the applied load, when bent about 70°. Thus, theeffect of a slightly thinner mat was noted for a shingle with scrimapplied thereto.

With reference now to FIG. 8, it will be seen that shingle versions 6and control shingles 6C were also shown as comprising a 235 lb. shingleby weight, and a 2½ lb. mat, but wherein, unlike the similar specimenindicated for FIG. 7, the specimen graphed in FIG. 8 had a 6 inch widescrim applied thereto. It will be seen that the control version of FIG.8 tested similarly to that of the control version of FIG. 7, and thatthe version with the 6 inch scrim applied thereto likewise testedsimilarly to that of the scrim-applied version of FIG. 7.

It has thus been found that the bending tests, performed with aTinius-Olsen Flexibility Tester to apply the force bending the shingletab portions 44 in the direction of the arrow 45 of FIG. 4 all show thatthe specimens with scrim reinforcement embedded on their rear sidesexhibit improved resistance to failure upon bending, and thus arecapable of maintaining and carrying applied stress due to bending tomuch higher degrees than shingle specimens without the scrim. Thus,shingles with the scrim applied thereto in accordance with thisinvention provide improved resistance to damage due to wind uplift.

Nail pull tests were run on a plurality of shingles, with and withoutreinforcement layers. The tests were run on 4 inch by 4 inch specimens,placed over a plate having a 2½ inch center hole, with the nail beingdriven through the shingle, so as to place the nail at the center of the2½ inch hole, which in turn is at the center of the 4 inch by 4 inchplate, and with the nail then being pulled upwardly to determine thestrength of the shingle in resisting failure or tearing against theforce of the nail pull. This is a standardized test for shinglespursuant to ASTM.

First, ten specimens of control shingles were tested, having noreinforcement layer on their rear surface. The resistance strength ofthe control samples prior to failure, averaged 29.69 lb.±3.78 lb.deviation over the ten shingles tested.

Next, ten specimens of the same type of shingle as the control shinglewere tested, but which deviated from the control shingle, in that theyhad a 17 gram polyester mat reinforcement layer on their rear surfaces.The resistance strength of these specimen resisting the nail pull, priorto failure, averaged 33.27 lb.±3.52 lb. deviation over the ten specimenstested.

Then, ten specimens of shingle constructed the same as the controlshingles, but different from the control shingles in that they each hada reinforcement layer on the rear surface, of 30 gram polyester mat. Theresistance strength, of these specimens in resisting the nail pull priorto failure averaged 36.96 lb.±3.98 lb. deviation over the ten specimenstested.

Then, ten specimens of the same type of specimens as the control shinglewere tested, but wherein the reinforcement layer was a fiberglass scrimhaving nine strands in the vertical direction and nine strands in thehorizontal direction per square inch (9×9 per in²). The ten specimenswith the fiberglass scrim on the rear surface averaged 54.13 lb.resistance to the nail pull test prior to failure, ±4.02 lb. deviationover the ten specimens tested.

These nail pull strength tests thus revealed that the fiberglass scrimas a reinforcement layer provided the greatest resistance prior tofailure, although each of the 17 gram polyester mat and 30 grampolyester mat provided greater resistance prior to failure than thecontrol specimens without any reinforcement layer.

It will thus be seen that, when nails or other fasteners are applied tothe shingle, for fastening the shingle to a roof, they pass through thereinforcement layer. This more securely fastens the shingle to a roof,and is especially desirable when applied to roofs having steep slopes,in that it can sometimes occur on very hot sunny days, on a steep roof,perhaps with workmen walking on the roof, that the stress on the shinglecan cause the shingle to tear above the fastening points and perhapsbecome dislodged from the roof. By fastening the shingle to a roofthrough the reinforcement zone in such a situation, the fasteners aremore prone to maintain the shingle adhered to the roof. This can beespecially so if the reinforcement material that is applied to the rearof the roof comprises a scrim of crossing strands, a fabric, or othermaterial that is resistant to tearing.

It will be apparent from the forgoing that various modifications may bemade in the details of construction, as well as with the use of shinglesof this invention, all within the spirit and scope of the invention asdefined in the appended claims.

What is claimed is:
 1. A shingle having front and rear exterior surfacesand being comprised of shingle material, with the shingle having a widthdefined by upper and lower edges and a length defined by right and leftedges, the shingle comprising: (a) a base layer of mat having front andrear surfaces; (b) a coating of asphaltic material on both front andrear surfaces of the mat; (c) coatings of granular material on said bothfront and rear surfaces of the mat, which, together with said base layerof mat and said coating of asphaltic material comprise a first thicknesslayer; (d) a longitudinal fastening zone between right and left shingleedges, generally intermediate said upper and lower edges; (e) and an atleast partially externally visible generally longitudinal reinforcementsecond thickness layer of a substantially thinner dimension than saidfirst thickness layer; said reinforcement second thickness layer beingadhered to an exterior surface of said shingle and extending at leastsubstantially between right and left edges of the shingle; and (f) saidreinforcement second thickness layer extending at least partially lowerthan the fastening zone, toward the lower edge of the shingle or atleast partially into the fastening zone toward the upper edge of theshingle, said reinforcement second thickness layer providing increasednail pull resistance.
 2. A roof with a plurality of shingles accordingto claim 1 fastened thereto.
 3. The shingle of claim 1, thereinforcement second thickness layer being selected from the groupconsisting of polyester mats and fiberglass scrims.
 4. The shingle ofclaim 1 wherein the increased nail pull resistance is statisticallysignificant at at least the 90 percent confidence level.
 5. The shingleof claim 1 wherein the reinforcement second thickness layer provides atleast a 12 percent increase in nail pull resistance.
 6. The shingle ofclaim 5 wherein the reinforcement second thickness layer provides atleast a 24 percent increase in nail pull resistance.
 7. A shingle havingfront and rear exterior surfaces and being comprised of shinglematerial, with the shingle having a width defined by upper and loweredges and a length defined by right and left edges, the shinglecomprising: (a) a base layer of mat having front and rear surfaces; (b)a coating of asphaltic material on both front and rear surfaces of themat; (c) coatings of granular material on said both front and rearsurfaces of the mat, which, together with said base layer of mat andsaid coating of asphaltic material comprise a first thickness layer; (d)a longitudinal fastening zone between right and left shingle edges,generally intermediate said upper and lower edges; (e) and an at leastpartially externally visible generally longitudinal reinforcement secondthickness layer of a substantially thinner dimension than said firstthickness layer; said reinforcement second thickness layer beingprovided on an exterior surface of said shingle and extending at leastsubstantially between right and left edges of the shingle; and (f) saidreinforcement second thickness layer extending at least partially lowerthan the fastening zone, toward the lower edge of the shingle or atleast partially into the fastening zone toward the upper edge of theshingle.
 8. A roof with a plurality of shingles according to claim 7fastened thereto.
 9. The shingle of claim 7, wherein the reinforcementsecond thickness layer is provided on the rear exterior surface of theshingle.
 10. A pair of laminated shingles applied to a roof in twoadjacent courses, each laminated shingle having a top sheet applied overa backing sheet, each backing sheet having a lower marginal edge, eachtop sheet having a headlap marginal edge, wherein the second course ofshingles is applied over the first course of shingles such that thelower marginal edge of the backing sheet of the second course ofshingles is coextensive with the headlap marginal edge of the top sheetof the first course of shingles; each shingle having front and rearexterior surfaces and being comprised of shingle material, with theshingle having a width defined by upper and lower edges and a lengthdefined by right and left edges, each shingle comprising: (a) a baselayer of mat having front and rear surfaces; (b) a coating of asphalticmaterial on both front and rear surfaces of the mat; (c) coatings ofgranular material on said both front and rear surfaces of the mat,which, together with said base layer of mat and said coating ofasphaltic material comprise a first thickness layer; (d) a longitudinalfastening zone between right and left shingle edges, generallyintermediate said upper and lower edges; and (e) an at least partiallyexternally visible generally longitudinal reinforcement second thicknesslayer of a substantially thinner dimension than said first thicknesslayer; said reinforcement second thickness layer being adhered to anexterior surface of said shingle, being at least partially within saidfastening zone and being at least substantially between right and leftedges of the shingle.
 11. A pair of shingles according to claim 10, withsaid reinforcement second thickness layer extending lower than thefastening zone, toward the lower edge of the shingle.
 12. A pair ofshingles according to claim 10, wherein the reinforcement secondthickness layer is on the rear exterior surface of the shingle.
 13. Apair of shingles according to claim 11, wherein the reinforcement secondthickness layer is on the rear exterior surface of the shingle.